Page 17 - Q & A STPM 2022 Biology

Biology STPM Chapter 3 Membrane Structure and Transport

Question 6
An example of a process that involves active transport is
A an influx of sodium ions into a nerve axon during the conduction of a
nerve impulse.
B the movement of sodium ions from glomerular filltrate into blood plasma
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during reabsorption in the nephron tubule.
C the movement of potassium ions from blood plasma into the lumen of a Semester
Bowman’s capsule during ultrafiltration.
D a shift of chloride ions across the membrane of a red blood cell during
carbon dioxide transport. 1

Answer : B
The movement of sodium ions into the axon of the nerve is through open
sodium channels. Ultrafiltration occurs in the glomerulus and Bowman’s
capsule. The chloride shift involves diffusion.

Question 7
A plant cell with a solute potential of –0.65 MPa maintains a constant volume
when immersed in a solution with a solute potential of –0.3 MPa. Which of
the following conclusion can be made about the cell?
A The pressure potential of the cell is +0.65 MPa.
B The water potential of the cell is –0.65 MPa.
C The pressure potential of the cell is +0.3 MPa.
D The pressure potential of the cell is +0.35 MPa.

Answer : D
The water potential of a plant is the sum of its solute potential and pressure
potential, ψ ψ ψ . P
S
2

Question 8
Plasma membrane is selectively permeable to certain substances. Which of the
following substances is / are not permeable to the cell surface membrane?
I Hydrophobic molecules
II Polar and tiny molecules
III Polar and large molecules
IV Ions
A IV only
B I and II only
C III and IV only
D I, II and III only

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Chapter 3.indd 57 11/2/21 9:21 AM